Feline urinary tract disease-detecting paper cat litter and method

ABSTRACT

A cat litter which comprises a plurality of lightweight, resilient paper strips treated with a pH-indicator and/or an occult blood indicator and folded transversely into generally zig-zag shapes, enables early detection of feline urological syndrome. When wetted with alkaline urine secreted by the cat, the paper strips treated with pH indicator exhibit a noticeable color change. When wetted with cat urine containing occult or gross blood, the paper strips treated with occult blood indicator exhibit a noticeable color change. A mixture of pH indicator treated strips and occult blood indicator strips in the cat litter enables the detection of both alkaline pH and occult blood in the same urine sample. The color changes are easily visible to the observer without requiring unsanitary contact with the cat litter.

RELATED APPLICATIONS

This application is a division of application Ser. No. 08/345,524 filedNov. 28, 1994 and a continuation-in-part application Ser. No. 08/153,360filed Nov. 16, 1993 abandoned and a continuation-in-part applicationSer. No. 08/125,310 filed Sep. 22, 1993, now abandoned, and acontinuation-in-part of PCT/US93/11085 filed Nov. 19, 1993.

Application Ser. No. 08/345,524 is a continuation-in-part applicationSer. No. 08/153,360 filed Nov. 16, 1993 abandoned and acontinuation-in-part of application Ser. No. 08/153,491 filed Nov. 17,1993 and a continuation-in-part application Ser. No. 08/125,310 filedSep. 22, 1993, now abandoned, and a continuation-in-part ofPCT/US93/11085 filed Nov. 19, 1993.

PCT/US93/11085 is a continuation-in part of application Ser. No.08/125,310 filed Sep. 22, 1993, now abandoned.

Application Ser. No. 08/153,360 is a continuation-in-part of applicationSer. No. 07/861,225 filed Mar. 31, 1992, now abandoned.

Application Ser. No. 08/153,491 is a continuation-in-part of applicationSer. No. 07/861,225 filed Mar. 31, 1992, now abandoned.

The entire disclosures of these prior applications are herebyincorporated by reference herein.

FIELD OF THE INVENTION

This invention relates generally to a cat litter, and more particularlyto a resilient paper cat litter and method for detecting feline diseaseswhich are indicated by a predetermined characteristic of the cat'surine, such as a particular pH range and/or blood in the cat's urine.Feline diseases which may be thus detected include feline urinary tractdiseases, such as feline urological syndrome ("FUS") or feline lowerurinary tract disease ("FLUTD"), and/or cystisis (bladder infection).

BACKGROUND OF THE INVENTION

FUS is a term used to describe a group of clinical signs and symptomsassociated with diseases of the urinary tract of male and female cats.Manifestations of FUS include frequent trips to the litter box,straining to urinate with little result, blood in the urine(particularly occult or microscopic blood in the early stages of thedisease), urination in inappropriate places, and even pain duringurination. The cat may also pace, lick itself, and cry.

The manifestations of FUS are often the result of the formation ofmineral crystals, usually struvite, in the cat's urine. Struvitecrystals are generally comprised of a magnesium ammonium phosphatecomplex. While some of these crystals may be passed, accumulation of thecrystals can occur in the cat's bladder and urethra, resulting inirritation of the lining of the bladder and urethral walls, making themmore prone to bacterial infection and microscopic bleeding. Infectionadds cellular debris to the crystal mix and may cause a blockage of theurinary tubes, particularly in male cats. Due to anatomic differences,primarily the smaller diameter of the urinary tubes in male cats, theurinary tract of an afflicted male cat can become completely blocked.The blocked cat may stop eating, vomit and become increasingly agitated.Most worrisome, the condition is immediately life-threatening. If ablocked cat does not receive emergency medical attention to relieve theblockage, the cat may die, in a matter of hours, from uremic poisoningand kidney failure.

Unfortunately, FUS is far too common. As many as 10% of all felineadmissions into a veterinary hospital are related to FUS. Mosttypically, FUS has been observed in overweight cats that have beenspayed or neutered, and are between 2-6 years of age.

It has been observed that the struvite crystals associated with FUS,which may lead to fatal blockage, generally form in more alkaline caturine. Consequently, a diet which causes the cat to excrete alkalineurine predisposes the cat to FUS. In addition, a dietary excess ofmagnesium and phosphorus will generally magnify the problem, presumablyby supplying the minerals needed to form struvite crystals in alkalineurine. Hence, FUS can sometimes be avoided by switching to a premiumbrand of cat food formulated to generate a slightly acidic urine andwhich has a relatively low magnesium and phosphorous content.

Regrettably, however, cat owners frequently mistake the initial symptomsof FUS for other problems, particularly constipation. To the owner, thecat's frequent trips to the litter box (where the cat may sit for longerperiods of time) indicates that the cat is constipated. Because the catgenerally does not have a fever, and appears otherwise normal, at leastin the initial stages of the disease, the owner too often assumes thatthe problem will pass. Even if the cat cries out in pain, the cat ownermay not realize that a life threatening condition is imminent.Consequently, there is a need for cat owners to be able to easilymonitor their cats' urine for the early signs of FUS, including thepresence of an alkaline pH and/or occult blood. (In contrast to redgross or frank blood, occult blood cannot be visually detected by thecat owner.)

Moreover, once a cat has been afflicted with FUS, the cat frequentlybecomes more succeptible to recurrence of the disease, even afterdiagnosis and treatment with a diet formulated to generate a more acidicurine. Owners of such cats need to be alerted to the continuing signs ofFUS, which can include occult or frank blood in the urine. In addition,blood in the urine can be a sign of other feline diseases, such ascystitis. Consequently, a convenient method of detecting blood in thecat's urine can also alert the cat owner to the presence of such otherdiseases, thereby ensuring that the cat gets prompt medical treatment.

As can be readily appreciated, however, it is difficult--if notimpossible--to get a cat to "give a sample" in which a pH- orblood-detecting test stick could be dipped. As can also be appreciated,particularly by cat owners, it would not be desirable to collect the caturine in the litter box for testing. For example, replacing conventionallitter (e.g. a processed, granular clay) with a material that does notabsorb urine might permit a test stick to be dipped into the urine whileit was still in the litter box; but the cat owner would then beconfronted with a messy testing and disposal problem, particularly iffrequent monitoring was sought. Moreover, it would be difficult for thecat owner to avoid unsanitary contact with the used cat litter, acontact made more particularly undesirable if the urine is contaminatedby bacteria from a bladder infection.

Alternatively, the cat owner might be provided with a product to beadded to conventional, used litter. Such a product would react to thepresence of an alkaline pH or occult blood in the urine by undergoing acolor change, for example. This approach, however, would betime-consuming and inconvenient, and would again expose the cat owner tothe risk of unsanitary contact with the used litter. Further, any colorchanges which might occur would be very difficult to see when such aproduct is added to conventional litter, e.g., clay, which already has abluish hue and turns even darker when wetted. Moreover, the cat ownerwould still confront the other problems associated with conventional catlitter, including its heavy weight, which makes transport of the litterdifficult, and the task of filling and cleaning the litter box. Inaddition, due to its "non-resilient" nature, large and bulky packagingarrangements are required to accommodate the desired volume ofconventional litter.

The drawbacks of the foregoing proposals would only be multiplied insituations outside the home where a large number of cats need to bemonitored; for example, in a pet shop, animal shelter and/or at aveterinarian's office. Accordingly, there remains a need for aninexpensive means for routinely and readily monitoring cat urine forsigns of FUS, cystitis and/or other feline diseases which are indicatedby a predetermined characteristic of the cat's urine, such as aparticular pH range and/or blood in the urine. There also remains a needfor a detection method which is convenient, easy to use, and acceptableto both the cat and its caregiver.

SUMMARY OF THE INVENTION

The present invention provides a cat litter comprising a light-weight,resilient paper product, which permits the cat owner or care giver todetect feline diseases that are indicated by a predeterminedcharacteristic of the cat's urine. The cat litter comprises a pluralityof longitudinal paper strips, folded transversely into generally zig-zagshapes. The paper strips are treated with a chemical indicator selectedto exhibit a noticeable color change when the treated paper strips arewetted with cat urine having the predetermined characteristic of thefeline disease.

By observing color changes in the cat litter, the cat owner can bereadily alerted to the warning sign(s) of the disease. Critical remedialaction, such as a change in diet and/or an immediate visit to theveterinarian, can then be taken by the cat owner.

Further, due to the zig-zag shapes of the paper strips, the litter isporous and resilient and can be compressed and then allowed to relax orexpand repeatedly. Hence, relatively large volumes can be compacted intosmall and/or light-weight packages, which are convenient and easy to useand carry. Also, the paper strips can be allowed to relax or expand inan intertwining and interlocking manner, thereby combining to formsubstantially a mass. The interlocking and intertwining of the paperstrips also prevents the cat from dragging pieces of the cat litter outof its box, thereby keeping the cat owner's home in a tidier condition.

The invention is particularly suited to detect FUS, conveniently andinexpensively, even in its early stages and/or for the post-diagnosismonitoring of cats with a history of FUS. When used to detect FUS, thepaper strips preferably comprise bleached, white Kraft paper, and havepreferably been treated with a pH indicator and/or an occultblood-indicator.

The pH indicator is selected to exhibit a marked color change when thetreated paper is exposed to alkaline cat urine. Preferred examplesinclude bromocresol purple, phenol red, and chlorophenol red.

Similarly, the occult blood indicator is selected to exhibit a markedcolor change when the treated paper is exposed to cat urine comprisingoccult blood and/or its by-products (e.g., hemoglobin). The occult bloodindicator preferably comprises guaiac, benzidine, ortho-tolidine,ortho-dianisidine, or other leuco-dyes, which produce a blue color inthe presence of microscopic blood and hemoglobin.

The cat litter preferably comprises a mixture of strips treated with thepH indicator and strips treated with the blood indicator. The indicatorsare preferably selected to undergo different color changes when exposedto an alkaline pH or occult blood in the urine, respectively. Then, whenthe cat uses the litter, the owner can readily determine simultaneouslyif the cat's urine is alkaline and/or contains blood.

Moreover, the presence of blood can alert the cat owner to the possiblepresence of cystitis or other feline diseases. In addition, gross redblood in the urine (another warning signal of feline disease) can beeasily observed by the cat owner, particularly when the treated paperstrips are manufactured from white Kraft paper.

The cat litter may also be treated with a sizing, in an amountsufficient to permit the urine to roll off the strips initially to thebottom of the cat litter, when the cat wets from the top of the litter.Then, the urine is more gradually absorbed by the strips, allowing themto become wetted from the bottom upwards. Consequently, the cat can bekept drier and more comfortable, thereby further encouraging use of thelitter.

In addition, the paper cat litter is biodegradable and therebyenvironmentally responsible, particularly when used in connection with adisposable container, as hereinafter described. In the presentinvention, the walls of the disposable container are preferably coatedwith a biodegradable, water-repellant and urine-resistant material. Inaddition, an absorbent paper sheet treated with an antibacterial and/oranti-odor substance is preferably placed under the treated paper strips,at the bottom of the container.

The present invention also provides a method for detecting felinediseases, particularly FUS, in a cat, which are indicated by apredetermined characteristic of the cat's urine. In this method, a webof paper material is treated with a chemical indicator selected toexhibit a marked color change when wetted by cat urine having thepredetermined characteristic. The treated paper is longitudinally cutinto a plurality of paper strips, which are folded transversely intogenerally zig-zag shapes.

The method is preferably employed to detect FUS. In this preferredembodiment, the method comprises treating the paper strips with a pHindicator and/or occult blood indicator, selected to exhibit a markedcolor change upon contact with alkaline cat urine and/or bloody urine,respectivley.

These and other features of the invention are fully described andparticularly pointed out in the claims. However, the particularembodiments depicted and exemplified are only illustrative of the rangeof ways by which the principles of the invention may be employed.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a perspective view of a disposable cat litter box containingan embodiment of the resilient, paper cat litter of the invention,wherein the cat litter box includes a container which is convertiblebetween closed and open conditions in which it respectively forms aclosed and open receptacle, the container being shown in the opencondition;

FIG. 2 is a perspective view of the cat litter box of FIG. 1, with thecontainer being shown in a partially opened condition;

FIG. 3 is a perspective view of the cat litter box of FIG. 1, with thecontainer being shown in the closed condition;

FIG. 4 is a partially cut-away perspective view of a different catlitter box containing the resilient paper cat litter of the invention,wherein the cat litter box includes a flat cover panel enclosing the catlitter, and in which cat litter box the cat litter is underlain by anabsorbent sheet of paper product that has been treated with anantibacterial and/or anti-odor substance.

FIG. 5 is a partially exploded and cut-away perspective view of the catlitter box of FIG. 4; and

FIG. 6 is a perspective view of a nested stack of six of the cat litterboxes of FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings in detail and initially to FIGS. 1, 2, 4,5, and 6, the feline disease detecting cat litter 20 of the presentinvention is exemplified. As illustrated and described in further detailherein, the cat litter 20 is preferably packaged and used in adisposable cat litter box 10 which is convertible between closed andopen conditions. These preferred cat litter boxes are disclosed in U.S.patent application Ser. No. 08/125,310 and/or PCT Patent Application No.PCT/US93/11085, both of which have previously been incorporated byreference herein. However, it is also contemplated that the cat litter20 can be packaged and used with other cat litter boxes and packagingmaterials.

In accordance with the invention, the cat litter comprises a resilientpaper product, which comprises a plurality of longitudinal paper strips.The strips have been folded transversely into generally zig-zag shapes,and treated with a chemical indicator selected to undergo a marked colorchange when the treated paper strips are wetted with cat urine having apredetermined sign or characteristic of the feline disease.

When used to detect FUS, the paper is preferably treated with a pHindicator and/or an occult blood indicator. More preferably, the catlitter comprises a mixture of pH- indicating and occult blood-indicatingpaper strips. The cat litter may also comprise a mixture of treatedstrips and untreated strips.

The pH indicator is selected so that the treated strips exhibit anoticeable color change when wetted with alkaline cat urine, which isone of the primarily early warning signals of FUS. Upon observing thecolor change, the cat owner can take prompt remedial action, such as achange in diet and/or a visit to the veterinarian, thereby avertingserious illness or even death of the cat. (By selecting a pH indicatorwhich changes color in acidic cat urine, the present invention can alsobe used to detect other feline diseases, which are known to becharacterized by acidic cat urine).

Normal cat urine has a pH value ranging between about 5.5 to about 6.6.Therefore, the selected pH indicator preferably exhibits a prominentcolor change at or above a selected pH value of about 6.8. Preferred pHindicators include bromocresol purple, which rapidly changes from yellowin acidic solutions to purple in alkaline solutions, over a pH range of5.2 to 6.8; chlorophenol red, which rapidly changes from yellow (acid)to red (alkaline), over a pH range of 5.2 to 6.8; and phenol red, whichalso rapidly changes from yellow (acid) to red (alkaline), over a pHrange of 6.6 to 8.0.

The occult blood indicator is selected to exhibit a marked color changein the presence of occult blood. Preferred indicators comprise guaiac,benzidine, ortho-tolidine, ortho-dianisidine, or other "leuco-dyes,"which turn various shades and intensities of blue, in the presence ofoccult blood, hemoglobin, or other peroxidase-containing bloodcomponents. (The peroxidase catalyzes the oxidation of the leuco-dye byperoxide, resulting in the color change.)

The strips comprising the cat litter are formed from a paper material.Preferably, the strips are made from thirty pound Kraft paper, whichpreferably comprises bleached white Kraft paper. It is contemplated,however, that other paper materials can be used, provided that thematerial does not resist treatment with the selected indicator, and isabsorptive to cat urine. Also, when treated with the selected indicator,the strips must undergo a noticeable color change when wetted with caturine having the predetermined sign(s) of the feline disease.

Further, the paper material should be biodegradable, and thusenvironmentally responsible. Moreover, it should be light-weight so asto provide a cat litter which can be easily carried and used.Preferably, the paper material is selected to provide a cat litterhaving a density of between about 0.01 to about 0.100 ounces per cubicinch and more preferably a density of approximately 0.035 inches percubic feet when compressed as when packaged in a cat litter container.

In addition, it should be recognized that the paper material for formingthe strips includes a natural resilience with a tendency to remain in astraightened form and to resist folding or bending. This principle canbe readily observed by simply taking a small sheet of Kraft paper andfolding it in half. Initially, when pressure is applied, the two halvesof the sheet between the fold are pressed together in close contact.When the pressure is released, however, the fold has a tendency to relaxor expand, thereby causing the halves to angularly separate.

Due to the foregoing characteristics, the paper strips, when foldedtransversely into zig-zag shapes, act like mini-springs, which can belongitudinally compressed and allowed to relax or expand repeatedly.Hence, relatively large volumes of the cat litter 20 of the presentinvention can be compacted into small and/or light-weight packages,which can be conveniently transported and stored. This feature providesan additional significant benefit to the manufacturer, dealers, andusers of the cat litter of this invention.

Moreover, when allowed to relax or expand, the resilient zig-zags canbecome intermixed and repositioned in an intertwining and interlockingmanner. Preferably, when the cat litter is in use, the strips have beenpermitted to intertwine and interlock sufficiently to form substantiallya mass. The interlocking and intertwining prevents the cat from draggingpieces of the cat litter out of its box, thereby keeping the cat owner'shome in a tidier condition.

Examples of suitable machines/methods for converting a continuous web ofpaper material into the plurality of zig-zag shaped strips comprisingthe cat litter of the present invention are disclosed in U.S. Pat. Nos.5,088,972; 5,134,013 and 5,173,352; and U.S. patent application Ser.Nos. 07/861,225, 07/971,046, and 08/153,360. (All of thesepatents/applications are assigned to the assignee of the presentinvention, and have been previously or are hereby incorporated herein.)In these machines/methods, a portion of the continuous web of papermaterial is withdrawn and cut into a plurality of strips by rotatingsets of cutting discs, thereby forming a body of such strips. Theplurality of strips are advanced against a restricting means acting onthe body of strips in such a manner that the natural resilience of thepaper causes the paper strips to be folded into generally zig-zagshapes, with substantially uniform adjacent and opposite planar portionsbetween the folds.

Using the preferred machines/methods, the tightness of the resultingfolds can be controlled by adjusting the speed at which the stripsadvance against the restricting means. A slower speed generates atighter fold or crimp. Applicants have observed that tighter foldspermit the zig-zag strips to become more thoroughly interlocked andintertwined. Thus, the speed can be regulated to provide a cat litterhaving the desired degree of interlocking and intertwining.

The continuous web of paper material employed is commonly supplied in acompact form, such as roll. Alternatively, as is disclosed in pendingU.S. application Ser. No. 07/994,940 (assigned to the assignee of thepresent invention), the disclosure of which is hereby incorporated byreference herein, the web of paper material could be fan-folded into arectangular stack.

The machine/method for converting the web of paper material into thezig-zag strips preferably incorporates a system for treating the paperwith the selected indicator. Examples of suitable machines/methods fortreating the paper strips with the indicator are disclosed in pendingU.S. application Ser. No. 08/153,360, previously incorporated herein.The preferred treatment method comprises providing a continuous web ofan untreated paper material; withdrawing a portion of the web to therebyform a withdrawn portion; applying the indicator in liquid phase to thewithdrawn portion of the paper material; and converting the treatedwithdrawn portion into the plurality of zig-zag shaped strips. Thepreferred treatment-applying device preferably includes a container ortrough which contains the indicator in the liquid phase, a roller whichis partially submerged within the liquid treatment and which contactsthe withdrawn portion, and a drive assembly which rotates the roller andthereby transfers the liquid treatment from the container to thewithdrawn portion.

The drive assembly of the preferred treatment system may include anadjustment mechanism which selectively varies the rotational speed ofthe roller for selectively varying the amount of the liquid treatmentbeing transferred to the withdrawn portion. The speed can then beadjusted as needed to treat the paper web with the indicator for a timeperiod sufficient to ensure that the resulting cat litter produces anoticeable color change when later wetted with cat urine having thepredetermined characteristic of the feline disease. Also, the rotationalspeed of the roller can be controlled to ensure that the paper web doesnot become so moistened that it loses its integrity or turns "mushy",thereby precluding the paper from being folded into resilient zig-zagshapes.

The pH indicator, when applied in liquid form, preferably comprises anaqueous solution. The indicator can be added to water (or another liquidbase) in either powdered or solution form. Suitable powdered or liquidforms of phenol red, chlorophenol red and bromocresol purple areavailable from the Aldrich Chemical Company, Milwaukee, Wis. Preferably,phenol red is used as an aqueous solution containing 0.1 percent weightper volume. Preferably, chlorophenol red and bromocresol purple are usedas aqueous solutions containing 0.04% weight per volume.

When the cat litter is prepared by moistening the paper with the liquidphase indicator prior to folding the resulting strips into zig-zagshapes, less pressure is generally required to initially impart a foldedmemory to the treated paper material. Additionally, when the foldsrelax, the angular separation between the folds is to a lesser degreethan that produced in the dry paper. Additionally, because theseparation is to a lesser degree, the folds tend to be more stable and,as the paper dries, tend to retain a smaller angle at the folds thanwould be accomplished over the same period of time at folds formed inthe drier sheet material. Thus, the preferred system for treating thepaper with the indicator provides a cat litter comprised of stripshaving improved "springiness." Hence, the degree of interlocking andintertwining of the strips and the resilient properties of the catlitter can be enhanced.

Although the cat litter (when used to detect FUS) may contain paperstrips which have been treated with pH indicator only or with occultblood indicator only, the preferred embodiment is a cat littercontaining a mixture of pH indicator-treated strips and occult bloodindicator-treated strips. The mixture preferably is a 50--50 mixture ofindicator strips; however, the ratio of indicator strips in the mixturemay vary according to which pH indicators and occult blood indicatorsare used. It is also contemplated that cat litter mixtures may alsocontain untreated paper strips. Regardless of the number or ratio ofindicator strips used, it is necessary that the resulting mixture ofpaper strips be sufficient to provide a noticeable color change of thetreated strips, in the presence of alkaline cat urine and/or cat urinecontaining occult blood. It is contemplated that mixing of the indicatorstrips may take place at any time during or after their manufacture,including mixing by the cat caregiver prior to use by the cat.

Untreated paper litter strips are preferably also treated with anodor-reducing or neutralizing agent. However, if treated paper stripsare used, any odor-reducing or neutralizing agent is preferably presentnot in the strips themselves, but in the absorbent pad 132 whichunderlies the paper strips, in order to minimize any chemicalinteraction between the treated strips and the neutralizing agent. Whenused in either untreated strips or in the absorbent pad, theodor-reducing or neutralizing agent is preferably present in a quantitysufficient to reduce the level of volatile odorant compounds (primarilyammonia generated by decomposing urine) in the cat litter 10 during thetime that it is made available for use by the cat. Preferredodor-reducing agents are disclosed in U.S. Pat. No. 4,938,957,incorporated by reference herein, and are available from EpoleonCorporation, Tokyo, Japan under the product name Epoleon N-100-65-2, andwhich contains the ingredients zinc phenolsulfonate, malic acid,diethanol amine and water in a composition of 21% weight of solids pervolume.

Additionally, the untreated or treated strips or the underlying pad mayalso be treated with an antibiotic or antibacterial material, such asneomycin. The quantity of antibiotic or antibacterial material issufficient to retard the growth of any bacterial species present in suchuse, for a period of time before the cat litter reaches a sanitarilyunacceptable condition. The preferred antibiotic is neomycin, in theform of neomycin sulfate, and is obtainable from The Upjohn Company,Kalamazoo, Mich.

The paper material can also be treated with a sizing, such as starch, inan amount sufficient to permit the urine to roll off the stripsinitially to the bottom of the cat litter, when the cat wets from thetop of the litter. The cat urine is then more gradually absorbed by thestrips, allowing them to become wetted from the bottom upwards.Consequently, the cat can be kept drier and more comfortable, therebyfurther encouraging use of the litter by the cat. The amount of sizingapplied, however, should not be so great that it prevents the cat urinefrom being absorbed into the paper, such that it collects at the bottomof the cat box, thereby precluding the cat owner from readily noticingthe color changes indicated by alkaline urine or occult blood, forexample (and creating a messy disposal problem). The amount of sizingapplied also must not be so great as to preclude absorption oradsorption of indicator during the liquid phase treatment of the paper.

As previously indicated, the cat litter 20 is preferably packaged andused in a disposable cat litter box which is convertible between closedand open conditions. Accordingly, the cat box may be compactly stored asa closed receptacle until ready for use, converted into an openreceptacle for use by the cat, and then converted back into a closedreceptacle for convenient and sanitary disposal.

In one preferred embodiment illustrated by FIGS. 1-3 (disclosed in U.S.patent application Ser. No. 08/125,310 and PCT Patent Application No.PCT/US93/11085, which have previously been incorporated by referenceherein), the cat litter box comprises a container 10 which isconvertible between a closed condition in which it forms a closedreceptacle (FIG. 3) and an open condition in which it forms an openreceptacle (FIG. 1). The conversion is accomplished by providing thecontainer 10 with appropriate sets of folding panels and appropriateinterconnections therebetween.

The container 10 is initially packaged and supplied in the closedcondition, with the cat litter 10 being enclosed within the closedreceptacle. When the container 10 is converted to the open condition,the open receptacle confines the cat litter 20 while at the same timepermitting a cat access for interaction with the cat litter 20.

The cat may then interact with the cat litter 20 until it reaches asanitarily unacceptable condition. Once the cat litter 20 reaches asanitarily unacceptable condition, the container 10 is converted backinto the closed receptacle to thereby enclose the sanitarilyunacceptable cat litter within the container 10. The container 10, andthe sanitarily unacceptable cat litter enclosed therein, may then bedisposed of as a unit. In this manner, the often unpleasant andunsanitary task associated with changing cat litter in conventionalboxes is eliminated.

The container 10 is made of material which is sufficient strength tofunction as a self-standing carton in its open condition and ofsufficient flexibility to convert between the open and the closedcondition. Preferably, the container 10 is made of a paper material sothat it is biodegradable and recyclable, and thus environmentallyresponsible. The container 10 should also be made of a light-weightmaterial, whereby the box's weight and size parameters do not nullifyits convenience in connection with disposal.

More preferably, the container 10 is made of corrugated cardboard asthis material economically provides the desired characteristics. In thepreferred embodiment, the container 10, when empty, weighs approximatelyone pound, and the completed cat litter box (i.e., the cat litter 20 andthe container 10 enclosing the litter) weighs approximately one andone-half pounds. By way of comparison, applicants' testing has proventhat if the preferred container 10 was filled with a conventional claylitter, it would weigh approximately from eight to nine pounds. Also byway of comparison, applicants' testing has proven that if the preferredcontainer 10 was filled with "scoopable" clay litter, it would weighapproximately from six to eight pounds. (Applicants note that thiscomparison may be somewhat conservative because it may actually requirea greater volume of clay litter and/or "scoopable" litter to replace theresilient paper cat litter 20.) Applicants contemplate a depth of theirfresh, resilient, low-density cat litter of about one and one-halfinches, whereas conventional clay kitty litters call for a depth of twoinches. In the above described comparative testing, applicants'containers were filled only to a depth of one and one-half inches with,respectively, the fresh cat litter of the present invention and clay catlitter.

In another preferred embodiment illustrated in FIGS. 4-6 (and disclosedin U.S. patent application Ser. No. 08/125,310 and PCT PatentApplication No. PCT/US93/11085, previously incorporated by referenceherein), the shape of the container allows multiple containers to benestably stacked. In this second preferred embodiment, the length andwidth of the bottom of a first container 110 fits easily within the openspace above the cat litter 20 defined by the portion of the wallsextending above the cover panel 160, of a second, lower container 110,whereby the bottom of the first container 110 preferably actually restsupon the cover panel 160 and partially within the walls of the lowercontainer 110 with which it is nested. Thus, while the container 110 mayhave a height of, e.g., four inches, when the container is nestablystacked in accordance with the invention, the container contributes onlyabout one and three-quarters inch to the total height of a nested stackof such containers.

In this embodiment of the invention, to convert the disposable catlitter box between the open and closed conditions, the user simplyremoves or replaces top panel 160 within the receptacle formed by panels131 and 133. When in the closed condition, top panel 160 will be incontact with the cat litter 20, and will resiliently compress cat litter20 somewhat. The compactability, in conjunction with the stackabilityand nestability of the preferred cat box, combine to provide unexpectedbenefits in cost savings and space savings during storage and shipping.

As illustrated in FIG. 4, the preferred embodiment also includes anabsorbent, anti-bacterial pad 132 positioned at the bottom of thecontainer 110. The preferred absorbent pad has approximately 28 poundweight, is unlined, and has been treated with a broad-spectrumantibiotic or antibacterial material such as neomycin. The mostpreferred absorbent paper material 132 is 28 pound Shoksorb withneomycin, available from Kieffer Paper Mills, Inc. Brownstown, Ind.47220.

The pad is also preferably treated with an odor-reducing or neutralizingagent, including those previously described herein. (Although notspecifically shown in these drawings, the cat litter of FIGS. 1-3 alsopreferably includes an absorptive pad treated with anti-bacterial andodor-neutralizing agents and positioned at the bottom of the container.)

Further, the walls of the preferred, disposable cat litter box arepreferably coated with a biodegradable, water-repellant andurine-resistant material. A preferred material is Michelman "42 KR", butother suitable materials are also available from Michelman,Incorporated, Cincinnati, Ohio.

Applicants contemplate that the cat litter of the invention, alone or inconjunction with the preferred disposable cat litter boxes, may be usedin the homes of cat owners to monitor feline diseases, particularly FUS,conveniently and inexpensively. Also, applicants contemplate that thecat litter would be advantageous in situations where a large number ofcats need to be monitored for FUS, such as at veterinarian offices orkennels, animal shelters and/or pet stores.

What is claimed is:
 1. A method of producing a cat litter, for detectinga feline disease which is indicated by a predetermined characteristic ofcat urine, which comprises a porous and resilient paper product, saidmethod comprising the steps of:providing a web of paper material havinga tendency to resist folding and including an indicator selected suchthat the paper material exhibits a marked color change when wetted withcat urine having the predetermined characteristic; cutting the web intoa plurality of longitudinal strips; folding said strips transverselyinto generally zig-zag shapes; and treating the paper material with asizing, in an amount sufficient to permit the litter to wet from bottomupwards, when a cat urinates on the top of the litter.
 2. The method ofclaim 1, wherein said strips are further permitted to intertwine andinterlock to combine and form a mass.
 3. The method of claim 1, whereinthe feline disease is FUS, the predetermined characteristic of the caturine is an alkaline pH, and the strips have been treated with a pHindicator selected such that the treated strips exhibit a noticeablecolor change when wetted with alkaline cat urine.
 4. The method of claim3, wherein the treated strips exhibit a noticeable color change whenwetted with alkaline cat urine having a pH at or above about 6.8.
 5. Themethod of claim 3, wherein the indicator is selected from the groupconsisting of bromocresol purple, chlorophenol red and phenol red. 6.The method of claim 1, wherein the feline disease is selected from thegroup consisting of FUS and cystitis, the predetermined characteristicof the cat urine is the presence of occult blood in the urine, and thestrips have been treated with a blood indicator selected such that thetreated strips exhibit a noticeable color change when wetted with caturine comprising occult blood.
 7. The method of claim 1 wherein theindicator comprises a leuco-dye.
 8. The method of claim 2, wherein themass has a density between about 0.01 and 0.100 ounces per cubic inch.9. The method of claim 1, wherein the paper material is biodegradable.10. The method of claim 1, wherein the paper material has further beentreated with a bacteria-preventing agent in an amount effective toretard the growth of bacteria associated with the cat urine.
 11. Themethod according to claim 1, wherein the providing step furthercomprises providing an untreated web of paper and treating the web withthe indicator.
 12. A method as set forth in claim 1 wherein the papermaterial is made of bleached Kraft paper.
 13. A method of producing acat litter, for detecting a feline disease which is indicated by apredetermined characteristic of cat urine and which comprises a porousand resilient paper product; said method comprising the stepsof:providing a web of paper material including an indicator causing thepaper material to exhibit a noticeable color change when wetted with caturine having the predetermined characteristic of the feline disease andtreated with a sizing in an amount sufficient to permit the litter towet from bottom upwards, when a cat urinates on top of the litter,cutting the web into a plurality of longitudinal strips; and foldingsaid strips transversely into generally zig-zag shapes.
 14. A method asset forth in claim 13 wherein the paper material is made of bleachedKraft paper.